title: The effect of variable doses of inorganic nitrate-rich beetroot juice on simulated 2,000-m rowing performance in trained athletes.
abstract: BACKGROUND
  Beetroot juice is a naturally rich source of inorganic nitrate (NO(3-)), a compound hypothesized to enhance endurance performance by improving exercise efficiency.
  
  
  OBJECTIVE
  To investigate the effect of different doses of beetroot juice on 2000-m ergometer-rowing performance in highly trained athletes.
  
  
  METHODS
  Ten highly trained male rowers volunteered to participate in a placebo-controlled, double-blinded crossover study. Two hours before undertaking a 2000-m rowing-ergometer test, subjects consumed beetroot juice containing 0 mmol (placebo), 4.2 mmol (SINGLE), or 8.4 mmol (DOUBLE) NO(3-). Blood samples were taken before supplement ingestion and immediately before the rowing test for analysis of plasma [NO(3-)] and [nitrite (NO(2-))].
  
  
  RESULTS
  The SINGLE dose demonstrated a trivial effect on time to complete 2000 m compared with placebo (mean difference: 0.2 ± 2.5 s). A possibly beneficial effect was found with DOUBLE compared with SINGLE (mean difference -1.8 ± 2.1 s) and with placebo (-1.6 ± 1.6 s). Plasma [NO(2-)] and [NO(3-)] demonstrated a dose-response effect, with greater amounts of ingested nitrate leading to substantially higher concentrations (DOUBLE > SINGLE > placebo). There was a moderate but insignificant correlation (r = -.593, P = .055) between change in plasma [NO(2-)] and performance time.
  
  
  CONCLUSIONS
  Compared with nitratedepleted beetroot juice, a high (8.4 mmol NO(3-)) but not moderate (4.2 mmol NO(3-)) dose of NO(3-) in beetroot juice, consumed 2 h before exercise, may improve 2000-m rowing performance in highly trained athletes.
authors.affiliation: Discipline of Exercise and Sports Science, University of Sydney, Lidcombe, NSW, Australia.
authors.forename: Matthew W
authors.initials: MW
authors.lastname: Hoon
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Jones
authors.forename: Nathan A
authors.initials: NA
authors.lastname: Johnson
authors.forename: Jamie R
authors.initials: JR
authors.lastname: Blackwell
authors.forename: Elizabeth M
authors.initials: EM
authors.lastname: Broad
authors.forename: Bronwen
authors.initials: B
authors.lastname: Lundy
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Rice
authors.forename: Louise M
authors.initials: LM
authors.lastname: Burke
mesh_terms: D000284:Administration, Oral; D027461:Beta vulgaris; D001628:Beverages; D018592:Cross-Over Studies; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005080:Exercise Test; D006801:Humans; D008297:Male; D009566:Nitrates / Q000008:administration & dosage* / Q000097:blood; D010101:Oxygen Consumption / Q000187:drug effects; D058573:Performance-Enhancing Substances / Q000008:administration & dosage* / Q000097:blood; D010807:Physical Endurance / Q000187:drug effects*; D010936:Plant Extracts / Q000008:administration & dosage* / Q000097:blood; D018517:Plant Roots; D013177:Sports; D013647:Task Performance and Analysis; D013997:Time Factors; D055815:Young Adult
chemical_list: D009566:Nitrates; D058573:Performance-Enhancing Substances; D010936:Plant Extracts